The present invention relates to motor-operated film winding apparatus for use with cameras in general and more particularly to an improved motor-operated film winding apparatus in which the degrading of power-supply performance is obviated.
Recently, there has been widely used film winding apparatus of the type operated by a motor, in which the motor is operated at a high speed with a high voltage applied to the motor when the film is wound continuously and, when the film is wound frame by frame, a low voltage is applied to the motor to operate the motor at a low speed, by switching the potential of the power source for the motor appropriately.
Conventionally, such switching of the potential of the power source is accomplished by utilizing a different number of batteries in each case. To be more specific, a high potential is obtained by utilizing all the batteries of the power source and a low potential is obtained by utilizing some limited number of particular batteries out of all the batteries.
However, when the batteries are used in the above-mentioned manner, such particular batteries tend to be exhausted more so that the internal resistances of the particular batteries increase. As a result, when the batteries having increased internal resistances are connected in series with the other batteries in order to turn the motor at a high speed, the total potential of the batteries is limited by the batteries having such increased internal resistances and this shortens the life of all the batteries employed in the camera.